JP2019173715A - Fuel injection device - Google Patents

Abstract

To provide a fuel injection device capable of supplying a required amount of fuel injection to an engine by preventing malfunction of an armature valve even when deposit caused by fuel occurs around the armature valve.SOLUTION: A fuel injection device includes a control chamber 10 disposed in opposition to an upper end portion 6a of a nozzle needle 6 to allow a fuel to flow therein, a discharge chamber 30 communicated to the control chamber 10 through a communication hole 13 to allow the fuel flowing into the control chamber 10 to flow therein through the communication hole 13, and an armature valve 25 for opening and closing the communication hole 13. The fuel injection device further includes a valve piece 35 having a second through hole 36, and supporting an outer peripheral face of the armature valve 25 by the second through hole 36. A second groove portion 38 connected to the second through hole is formed on the opening portion of the second through hole 36, and the second groove portion 38 has a second bottom surface 38b inclined so that a groove depth is deepened in accordance with separating from a central axis of the second through hole 36.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel injection device (injector) for injecting fuel into a combustion chamber of an engine.

  A fuel injection device that injects fuel into a combustion chamber such as a diesel engine is provided with a main body part in which a fuel injection hole for injecting fuel is formed at one end and a reciprocating motion inside the main body part, and opens and closes the fuel injection hole A nozzle needle. The fuel injection device is formed inside the main body so as to face the end opposite to the fuel injection hole side of the nozzle needle, and a control chamber through which a fuel flows and a control chamber A discharge chamber into which the fuel that has flowed into the control chamber flows through the communication passage, and an armature valve that opens and closes the communication passage. In the fuel injection device, by opening the communication path by the armature valve, the fuel in the control chamber flows out to the discharge chamber, and the pressure of the fuel in the control chamber is reduced. As a result, the force that presses the nozzle needle toward the fuel injection hole by the fuel in the control chamber is reduced, so that the nozzle needle moves to the opposite side of the fuel injection hole, the fuel injection hole is opened, and combustion from the fuel injection hole occurs. Fuel will be injected into the chamber.

In the above-described fuel injection device, Patent Document 1 discloses an armature valve configured not to receive a high fuel pressure. The armature valve is provided with an opening / closing valve at the tip thereof, and has a through hole at the axial center, and an armature bolt is inserted into the through hole. The outer periphery of the armature valve is supported in a through hole provided in the valve piece. Since such an armature valve does not receive a high fuel pressure, it has an advantage that power consumption required to open and close the armature valve can be kept low.

Special table 2012-526227 gazette

However, in the armature valve of Patent Document 1, the gaps between the armature bolt and the through hole of the armature valve, the outer periphery of the armature valve and the through hole of the valve piece are very narrow, and a deposit caused by fuel is generated. There is. In particular, in a fuel injection device that uses biofuel, such as FAME (Fatty Acid Methyl Ester), deposits are more likely to be generated in the narrow gaps described above, and this amount is larger than fuel injection devices that use ordinary fuel. In this case, the armature valve slides, and there is a possibility that a desired fuel injection amount cannot be supplied from the fuel injection device to the engine.

  The present invention has been made in view of the above problems, and even when deposits caused by fuel occur around the armature valve, it is possible to prevent malfunction of the armature valve and supply a desired fuel injection amount to the engine. A fuel injection device is provided.

  A fuel injection device according to the present invention includes a main body portion in which a fuel injection hole for injecting fuel is formed at one end, a nozzle needle that is reciprocally provided inside the main body portion, and that opens and closes the fuel injection hole, A control chamber that is formed inside the main body so as to face a first end that is the end opposite to the fuel injection hole side of the nozzle needle, and through a communication path An armature that communicates with the control chamber and that allows the fuel that has flowed into the control chamber to flow in through the communication passage, and is provided in the main body so as to be reciprocally movable. The armature opens and closes the communication passage by the reciprocation. The armature valve comprises: an armature plate portion; and a shaft-shaped valve needle portion extending from the armature plate portion and having a valve function for opening and closing the communication passage at a distal end portion; Having a through-hole, In the fuel injection device provided with a valve piece for supporting the outer peripheral surface of the valve needle portion by a through hole, the second through hole is continuously provided in an opening portion of the second through hole facing the armature plate portion. A second groove portion is formed, and the second groove portion is formed to have a second bottom surface that is inclined so that the depth of the groove becomes deeper as the distance from the central axis of the second through hole increases. It is.

  Moreover, the 2nd chamfer part may be provided in the cross | intersection location of the said 2nd groove part and the said 2nd through-hole.

The second chamfered portion may be formed in an arc shape.

  In the fuel injection device according to the present invention, even if a deposit caused by the fuel is generated between the armature valve and the second through hole of the valve piece, the second groove portion connected to the second through hole of the valve piece. As the deposit is discharged and the distance from the central axis of the second through hole is increased, the deposit moves to the outside in the radial direction of the second groove portion along the bottom surface that is inclined so that the depth of the groove is increased. Since the amount of deposit accumulated in the opening of the through hole can be reduced, the increase in sliding resistance of the armature valve due to deposit is suppressed, the malfunction of the fuel injection device is prevented, and the desired fuel injection amount is set to the engine. Can be supplied to.

  Further, in the fuel injection device according to the present invention, the second chamfered portion is provided at the intersection of the second groove portion and the second through hole, so that the deposit can be easily discharged into the second groove portion, and the second through hole and the armature. The amount of deposit remaining on the sliding surface of the valve can be reduced. As a result, the amount of deposit serving as the operating resistance of the armature bolt can be reduced, and malfunction of the fuel injection device can be prevented.

  Further, in the fuel injection device according to the present invention, the first chamfered portion is formed in an arc shape, so that the deposit is easily discharged into the first groove portion, and the sliding surface of the first through hole and the armature bolt is provided. It is possible to reduce the amount of deposits remaining in the substrate. As a result, the amount of deposit serving as the operating resistance of the armature bolt can be reduced, and malfunction of the fuel injection device can be prevented.

It is sectional drawing which shows the fuel-injection apparatus which concerns on embodiment of this invention. It is the A section enlarged view of FIG. 4 schematically shows a process in which deposits are accumulated between an armature bolt and an armature valve in a conventional fuel injection device. (A) is an initial state of deposit accumulation, and (b) is a state after a lapse of time after (a). 4 schematically shows a process in which deposit is accumulated between an armature bolt and an armature valve in a fuel injection device according to the present invention. (A) is an initial state of deposit accumulation, and (b) is a state after a lapse of time after (a). It is the B section enlarged view of FIG. 4 schematically shows a process in which deposits are accumulated between an armature valve and a valve piece in a conventional fuel injection device. (A) is an initial state of deposit accumulation, and (b) is a state after a lapse of time after (a). 4 schematically shows a process in which deposit is accumulated between an armature valve and a valve piece in the fuel injection device according to the present invention. (A) is an initial state of deposit accumulation, and (b) is a state after a lapse of time after (a).

Embodiments relating to the fuel injection device of the present invention will be specifically described below. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.
In the present embodiment, the end on the side where the fuel injection hole is formed is the lower end of the fuel injection device, and the end opposite to the end on the fuel injection hole side is the upper end of the fuel injection device. The fuel injection device will be described.

[overall structure]
FIG. 1 is a cross-sectional view showing a fuel injection device according to an embodiment of the present invention.
The fuel injection device 100 includes a main body 1 in which a fuel injection hole 3 for injecting fuel is formed at the lower end. In the present embodiment, the main body 1 is composed of a nozzle main body 2, a union nut 4 and a first closing plate 5. In addition, these components which comprise the main-body part 1 are an example to the last. Depending on the design of the fuel injection device 100, the number of parts constituting the main body 1 can be arbitrarily changed. The fuel injection valve 100 is attached to an internal combustion engine (not shown) or the like so that the fuel injection hole 3 side is lower in the direction of gravity than the first closing plate 5 side.

  The nozzle body 2 constitutes a lower portion of the body portion 1. The union nut 4 constitutes the upper part of the main body 1 and is formed in a cylindrical shape. The nozzle body 2 is airtightly fixed to the lower end portion of the union nut 4 by, for example, press fitting. The upper end of the union nut 4 is airtightly closed by the first closing plate 5.

  A high pressure chamber 52 is formed inside the nozzle body 2. The high-pressure chamber 52 is supplied with high-pressure fuel from the outside (for example, a common rail, a fuel pump, etc.) via a fuel inlet 51 formed in the nozzle body 2 and the union nut 4. A fuel injection hole 3 is formed at the lower end of the nozzle body 2. Through the fuel injection hole 3, the high-pressure fuel in the high-pressure chamber 52 is injected into a combustion chamber (not shown).

  The upper end portion of the high pressure chamber 52 is defined by the second closing plate 21. The second closing plate 21 is sandwiched between the fixing ring 4 a attached to the inner peripheral surface of the union nut 4 and the nozzle body 2 and closes the high-pressure chamber 52 in an airtight manner. A cylindrical protrusion that surrounds the control chamber 10 is formed on the surface of the second closing plate 21 on the high pressure chamber 52 side. The end of the cylindrical protrusion on the fuel injection hole 3 side is closed by a wall 11. The wall 11 is formed with a nozzle needle opening into which a nozzle needle 6 described later is inserted. In addition, a first throttle hole 12 that allows the control chamber 10 and the high-pressure chamber 52 to communicate with each other is formed in the cylindrical protrusion that surrounds the control chamber 10. That is, the high-pressure fuel in the high-pressure chamber 52 flows into the control chamber 10 through the first throttle hole 12.

  A nozzle needle 6 is provided inside the nozzle body 2 so as to be reciprocating along the axis of the high-pressure chamber 52 (movable up and down in FIG. 1). The nozzle needle 6 opens and closes the fuel injection hole 3. The nozzle needle 6 has an upper end portion 6a on the control chamber 10 side and a lower end portion 6b on the fuel injection hole 3 side. In addition, the nozzle needle 6 can also be comprised integrally, or can also be comprised from the some component operatively connected mutually. Here, the upper end portion 6a corresponds to the first end portion of the present invention.

  An upper end 6 a of the nozzle needle 6 is inserted into a nozzle needle opening formed in the wall 11 and protrudes into the control chamber 10. In other words, it can be said that the control chamber 10 is formed in the main body 1 so as to face the upper end 6 a of the nozzle needle 6. In addition, a hook-shaped protrusion 8 is formed on the outer peripheral surface of the nozzle needle 6 at a position below the wall 11.

  A spring 9 that urges the nozzle needle 6 toward the fuel injection hole 3 is provided between the protrusion 8 and the wall 11. Further, a step portion 7 is formed above the lower end portion 6 b of the nozzle needle 6. When the pressure of the high-pressure fuel in the high-pressure chamber 52 acts on the stepped portion 7, a force in a direction away from the fuel injection hole 3 is applied to the nozzle needle 6. A portion connected to the fuel injection hole 3 in the nozzle body 2 is formed with a seat portion, and the fuel injection hole 3 is closed when the nozzle needle 6 is seated (seat) with respect to the seat portion. No high pressure fuel is injected from the fuel injection hole 3. On the other hand, when the nozzle needle 6 is separated (lifted) from the seat portion, the fuel injection hole 3 is opened, and the high pressure fuel in the high pressure chamber 52 is injected from the fuel injection hole 3.

A communication hole 13 is formed in the second closing plate 21, and an annular sheet portion 21 a is provided coaxially with the communication hole 13 on the outer peripheral side of the opening of the communication hole 13. The seat portion 21 a constitutes a valve portion 25 a of an armature valve 25 (described later) and an on-off valve 20. Further, the second closing plate 21 is formed with a second throttle hole 14 that allows the control chamber 10 and the communication hole 13 to communicate with each other.

A valve piece 35 is attached to the surface of the second closing plate 21 opposite to the control chamber 10. The valve piece 35 has a cylindrical wall 31 and a wall 33 that closes the upper end of the wall 31, and forms a discharge chamber 30 surrounded by these walls 31 and 33. The wall 33 of the valve piece 35 is provided with a second through hole 36 having a circular inner periphery. The axis of the second through hole 36 is an axis in the same direction as the axis of the communication hole 13. Preferably, the axis of the second through hole 36 is on the same axis as the axis of the communication hole 13.

The armature valve 25 includes an armature plate portion 27 and a shaft-shaped valve needle portion 29 extending perpendicularly from the plate surface of the armature plate portion 27. Both the armature plate portion 27 and the valve needle portion 29 are valve needles. A first through hole 26 having a circular inner periphery that penetrates in the same direction or the same axis as the axis of the portion 29 is provided. An armature bolt 61 having a circular outer periphery is inserted into the first through hole 26, and the outer peripheral surface of the armature bolt 61 and the inner peripheral surface of the first through hole 26 constitute a sliding surface, and the pressure of the fuel It is comprised so that it may have oil-tightness. Further, the outer peripheral surface of the valve needle portion 29 is also circular, and the outer peripheral surface of the valve needle portion 29 and the inner peripheral surface of the second through hole 36 provided in the valve piece 35 similarly constitute a sliding surface, and fuel. It is comprised so that it may be oil-tight with respect to the pressure of this.

A distal end portion of the valve needle portion 29 of the armature valve 25 has an annular valve portion 25a that constitutes the on-off valve 20 in cooperation with the seat portion 21a provided on the second closing plate 21 described above. That is, when the armature valve 25 moves in the direction of the second closing plate 21 and the valve portion 25a at the tip of the valve needle portion 29 comes into contact with the seat portion 21a, the opening / closing valve 20 is closed, and the armature valve 25 is in the second state. When the valve member 25a moves in the direction opposite to the closing plate 21 and the valve portion 25a at the tip of the valve needle portion 29 is separated from the seat portion 21a, the on-off valve 20 is opened.

  By opening the on-off valve 20 as described above, the control chamber 10 and the discharge chamber 30 communicate with each other via the communication passage including the second throttle hole 14 and the communication hole 13. For this reason, the fuel in the control chamber 10 flows into the discharge chamber 30 through the communication path. Here, the flow path cross-sectional area of the second throttle hole 14 is larger than the flow path cross-sectional area of the first throttle hole 12 that communicates the high pressure chamber 52 and the control chamber 10. For this reason, when the on-off valve 20 is opened, the amount of fuel flowing out from the control chamber 10 into the discharge chamber 30 becomes larger than the amount of fuel flowing into the control chamber 10 from the high pressure chamber 52. Therefore, when the on-off valve 20 is opened, the fuel pressure in the control chamber 10 becomes lower than the fuel pressure in the high-pressure chamber 52.

  For example, two outlet holes 32 are formed in the wall 31 surrounding the discharge chamber 30 of the valve piece 35. The outlet hole 32 is a hole that communicates the discharge chamber 30 with the low-pressure chamber 53 formed above the second closing plate 21 in the union nut 4. The low pressure chamber 53 communicates with a fuel outlet 54 for discharging the fuel supplied into the fuel injection device 100 to the outside. For this reason, a high fuel pressure is not formed in the low pressure chamber 53.

  A spring 42 is disposed between the armature plate 27 and the first closing plate 5. The spring 42 moves the armature plate portion 27 in the direction of the second closing plate 21 so that the valve portion 25a of the valve needle portion 29 is pressed by the seat portion 21a provided on the second closing plate 21 and the space between the two is closed. Energize.

  An electromagnet 43 is provided between the armature plate portion 27 and the first closing plate 5. When power is supplied to the electromagnet 43, the armature plate portion 27 is attracted to the electromagnet 43, and the armature valve 25 moves upward against the force of the spring 42. That is, when electric power is supplied to the electromagnet 43, the on-off valve 20 opens a communication path that connects the control chamber 10 and the discharge chamber 30. When the on-off valve 20 opens the communication path, the fuel in the control chamber 10 flows into the discharge chamber 30 as described above, and further passes through the outlet hole 32 from the discharge chamber 30 and further into the low pressure chamber 53 and the fuel outlet 54. Spill into.

When the fuel pressure in the control chamber 10 decreases due to the outflow of fuel from the control chamber 10, the pressure of the fuel in the control chamber 10 and the force by which the spring 9 pushes the nozzle needle 6 toward the fuel injection hole 3 are 6, the nozzle needle 6 moves in the direction opposite to the fuel injection hole 3 to open the fuel injection hole 3. . Thereby, the fuel in the high pressure chamber 52 is injected through the fuel injection hole 3 into a combustion chamber (not shown).
That is, the fuel injection device 100 according to the present embodiment is a fuel injection device that applies the pressure of the fuel in the control chamber 10 to the upper end portion 6 a of the nozzle needle 6 and uses the pressure for driving the nozzle needle 6. .

When the supply of power to the electromagnet 43 is stopped, the armature valve 25 is pressed against the seat portion 21a of the second closing plate by the spring 42, and the on-off valve 20 closes the communication path that connects the control chamber 10 and the discharge chamber 30. . When the on-off valve 20 closes the communication path, the fuel pressure in the control chamber 10 increases, and the pressure of the fuel in the control chamber 10 and the force by which the spring 9 pushes the nozzle needle 6 toward the fuel injection hole 3 6 is larger than the force pushing the nozzle needle 6 acting on the step portion 7 and its lower end portion 6b in the direction opposite to the fuel injection hole 3, and the nozzle needle 6 moves in the direction of the fuel injection hole 3, Block. As a result, fuel injection stops.

A pressure sensor 63 is disposed on the upper end surface of the armature bolt 61 so that the pressure sensor 63 can detect a force acting on the lower end surface of the armature bolt 61.

[About the boundary between the opening of the first through hole 26 and the armature bolt 61]
FIG. 2 is an enlarged view of a portion A in FIG. A first groove portion 28 connected to the first through hole 26 is formed in the opening portion of the first through hole 26 in the armature plate portion 27. The first groove portion 28 has a first bottom portion 28b that is inclined so that the depth of the groove becomes deeper as the distance from the first through hole 26 increases. A first chamfered portion 28 a is provided at the intersection of the first groove portion 28 and the first through hole 26. The first chamfered portion 28a may be an arc-shaped chamfer, a C chamfer, or a chamfer at an angle other than 45 degrees.

  When the inner peripheral surface of the first through hole 26 and the outer peripheral surface of the armature bolt 61 slide along with the operation of the armature valve 25, deposits resulting from fuel may be generated on the sliding surface. In particular, in a fuel injection device that uses biofuel, such as FAME (Fatty Acid Methylester), deposits are more likely to be generated on the sliding surface than a fuel injection device that uses ordinary fuel.

FIG. 3 shows the movement of the deposit generated on the sliding surface of the armature bolt 61 and the first through hole 26 of the armature plate 27 ′ that does not have the first groove portion, which is a conventional product. A part of the deposit generated on the sliding surface moves to the opening of the first through hole 26 (FIG. 3A). The moved deposit gradually accumulates in the opening of the first through hole 26 (FIG. 3B). When the accumulated amount of deposit increases, the operating resistance of the armature valve 25 ′ is generated, and the operation of the armature valve 25 ′ is delayed. Due to the operation delay of the armature valve 25 ′, the operation of the nozzle needle 6 is also delayed, and there is a possibility that a desired fuel injection amount cannot be supplied from the fuel injection device to the engine at a desired timing. Further, the deposit that does not move to the opening and remains on the sliding surface similarly becomes the operating resistance of the armature valve 25 '.

FIG. 4 shows the movement of the deposit generated on the sliding surface of the first through hole 26 of the armature plate 27 and the armature bolt 61 in the embodiment of the present invention. Part of the deposit generated on the sliding surface moves to the first groove 28 connected to the first through hole 26 (FIG. 4A). The deposit moved to the first groove portion 28 has a diameter of the first groove portion due to the influence of gravity or the like along the first bottom portion 28b inclined so that the depth of the groove increases as the distance from the first through hole increases. It moves outward in the direction (FIG. 4B). Therefore, the amount accumulated in the opening of the first through hole 26 can be reduced as compared with the conventional product. In addition, since the first chamfered portion 28 a is provided at the intersection of the first groove portion 28 and the first through hole 26, the generated deposit is easily discharged to the first groove portion 28. As a result, the amount of deposit remaining on the sliding surface of the armature bolt 61 can be reduced. Thus, according to the present invention, the amount of deposit that becomes the operating resistance of the armature valve 25 can be reduced, and malfunction of the fuel injection device can be prevented.

[About the boundary between the opening of the second through hole 36 and the outer peripheral surface of the valve needle 29]
FIG. 5 is an enlarged view of a portion B in FIG. A second groove portion 38 connected to the second through hole 36 is formed in the opening of the second through hole 36 in the valve piece 35. Further, the second groove portion 38 has a second bottom portion 38b that is inclined so that the depth of the groove becomes deeper as the distance from the second through hole 36 increases. A second chamfered portion 38 a is provided at the intersection of the second groove portion 38 and the second through hole 36. The second chamfered portion 38a may be an arc-shaped chamfer, a C chamfer, or a chamfer at an angle other than 45 degrees.

When the inner peripheral surface 36a of the second through hole 36 and the outer peripheral surface 29a of the valve needle portion 29 slide along with the operation of the armature valve 25, deposits resulting from fuel may be generated on the sliding surface. In particular, in a fuel injection device that uses biofuel, such as FAME (Fatty Acid Methylester), deposits are more likely to be generated on the sliding surface than a fuel injection device that uses ordinary fuel.

FIG. 6 shows the movement of the deposit generated on the sliding surface of the second through hole 36 of the valve piece 35 ′ that does not have the second groove portion and the valve needle portion 29, which is a conventional product. A part of the deposit generated on the sliding surface moves to the opening of the second through hole 36 (FIG. 6A). The deposited deposit gradually accumulates in the opening of the second through hole 36 (FIG. 6B). When the accumulated amount of deposit increases, the operating resistance of the armature valve 25 ′ is generated, and the operation of the armature valve 25 ′ is delayed. Due to the operation delay of the armature valve 25 ′, the operation of the nozzle needle 6 is also delayed, and there is a possibility that a desired fuel injection amount cannot be supplied from the fuel injection device to the engine at a desired timing. Further, the deposit that does not move to the opening and remains on the sliding surface similarly becomes the operating resistance of the armature valve 25 '.

FIG. 7 shows the movement of the deposit generated on the sliding surface of the second through hole 36 of the valve piece 35 and the valve needle portion 29 in the embodiment of the present invention. A part of the deposit generated on the sliding surface moves to the second groove portion 38 connected to the second through hole 36 (FIG. 7A). The deposit moved to the second groove portion 38 has a diameter of the second groove portion due to the influence of gravity or the like along the second bottom portion 38b inclined so that the depth of the groove increases as the distance from the second through hole increases. It moves outward in the direction (FIG. 7B). Therefore, the amount of deposit accumulated in the opening of the second through hole 36 can be reduced as compared with the conventional product. In addition, since the second chamfered portion 38 a is provided at the intersection of the second groove portion 38 and the second through hole 36, the generated deposit is easily discharged to the second groove portion 38. As a result, the amount of deposit remaining on the sliding surface of the armature valve 25 can be reduced. Thus, according to the present invention, the amount of deposit that becomes the operating resistance of the armature valve 25 can be reduced, and malfunction of the fuel injection device can be prevented.

DESCRIPTION OF SYMBOLS 1 Main body part, 2 Nozzle main body, 3 Fuel injection hole, 4 Union nut, 4a Fixing ring, 5 1st obstruction board, 6 Nozzle needle, 6a Upper end part, 6b Lower end part, 7 Step part, 8 Protrusion part, 9 Spring, DESCRIPTION OF SYMBOLS 10 Control chamber, 11 Wall, 12 1st throttle hole, 13 Communication hole, 14 2nd throttle hole, 20 On-off valve, 21 2nd obstruction board, 21a Seat part, 25 Armature valve, 25 'Armature valve (conventional), 25a Valve portion, 26 First through hole, 27 Armature plate portion, 27 'Armature plate portion (conventional), 28 First groove portion, 28a First chamfered portion, 28b First bottom portion, 29 Valve needle portion, 30 Discharge chamber, 31 Wall , 32 outlet hole, 33 wall, 35 valve piece, 35 'valve piece (conventional), 36 second through hole, 38 second groove, 38a second chamfer, 38b second bottom, 42 spring, 43 electromagnet, 51 fuel entrance 52 high pressure chamber 53 low pressure chamber, 54 a fuel outlet, 61 armature bolt, 63 pressure sensor, 100 a fuel injection system.

Claims (3)

A main body formed with a fuel injection hole at one end for injecting fuel;
A nozzle needle that is reciprocally movable inside the main body and opens and closes the fuel injection hole;
A control chamber formed inside the main body so as to face a first end which is an end opposite to the fuel injection hole side of the nozzle needle;
A discharge chamber that communicates with the control chamber via a communication passage, and the fuel that has flowed into the control chamber flows through the communication passage;
An armature valve provided inside the main body so as to freely reciprocate and opens and closes the communication path by the reciprocation;
With
The armature valve is composed of an armature plate portion and a shaft-shaped valve needle portion extending from the armature plate portion and having a valve function for opening and closing the communication path at a tip end portion,
In the fuel injection device having a second through hole and provided with a valve piece that supports the outer peripheral surface of the valve needle portion by the second through hole,
A second groove portion connected to the second through hole is formed in the opening portion of the second through hole facing the armature plate portion,
The fuel injection device according to claim 1, wherein the second groove portion has a second bottom surface that inclines so that the depth of the groove increases as the distance from the central axis of the second through hole increases. 2. The fuel injection device according to claim 1, wherein a second chamfered portion is provided at an intersection of the second groove portion and the second through hole. The fuel injection device according to claim 1 or 2, wherein the second chamfered portion is formed in an arc shape.

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